Photos: Tyrann Mathieu

Photos: Tyrann Mathieu

Cardinals' Tyrann Mathieu watches practice from a distance during the team's first practice at University of Phoenix Stadium on July 29, 2016 in Glendale, Ariz.
Patrick Breen/azcentral sports

Photos: Tyrann Mathieu

Tyrann Mathieu poses for photos at the Red Carpet Premiere of "All or Nothing: A Season with the Arizona Cardinals" on Amazon at Tom’s Urban in Los Angeles, Calif., on Thursday, June 9, 2016.
Rob Schumacher/azcentral sports

Photos: Tyrann Mathieu

Carson Palmer, team president Michael Bidwill, Tyrann Mathieu, GM Steve Keim, Mike Iupati, David Johnson, singer Jordin Sparks, Michael Floyd, Calais Campbell and Patrick Peterson pose for photos at the premiere of "All or Nothing: A Season with the Arizona Cardinals" at Tom’s Urban in Los Angeles, Calif., on Thursday, June 9, 2016.
Rob Schumacher/azcentral sports

Photos: Tyrann Mathieu

Tyrann Mathieu arrives for the Arians Family Foundation Fundraiser at Steak 44 on Sunday, May 22, 2016 in Phoenix, Ariz.
David Kadlubowski/azcentral sports

Photos: Tyrann Mathieu

Tyrann Mathieu at the start of the 12th Annual Pat's Run at Sun Devil Stadium early Saturday morning, April 23, 2016.
Tom Tingle/azcentral sports

Photos: Tyrann Mathieu

Arizona Cardinals safety Tyrann Mathieu puts a brace on his knee while cleaning out his locker at the team's training facility in Tempe, Ariz. January 25, 2016.
Michael Chow/azcentral sports

Photos: Tyrann Mathieu

Arizona Cardinals free safety Tyrann Mathieu (32) watches his team in their win over the Green Bay Packers in their divisional playoff game Saturday, Jan. 16, 2016 in Glendale, AZ
David Kadlubowski/azcentral sports

Photos: Tyrann Mathieu

Tyrann Mathieu of the Cardinals sits on the sidelines during the first quarter of the NFC Divisional playoff game against the Packers at the University of Phoenix Stadium in Glendale, Az., on Saturday, January 16, 2016.
Rob Schumacher/azcentral sports

Photos: Tyrann Mathieu

Photos: Tyrann Mathieu

Arizona Cardinals free safety Tyrann Mathieu (32) celebrates his interception against the San Francisco 49ers in the 2nd quarter of their NFL game Sunday, Sept. 27, 2015 in Glendale, Ariz.
David Kadlubowski/azcentral sports

Photos: Tyrann Mathieu

Arizona Cardinals Tyrann Mathieu against the Minnesota Vikings in the second half on Dec. 10, 2015 in Glendale, Ariz.
Rob Schumacher/azcentral sports

Photos: Tyrann Mathieu

Arizona Cardinals Tyrann Mathieu displays his frustration against the San Francisco 49ers in the second half on Nov. 29, 2015 in Santa Clara, Calif.
Rob Schumacher/azcentral sports

Photos: Tyrann Mathieu

Arizona Cardinals safety Tyrann Mathieu waits to be introduced before playing against the St. Louis Rams at University of Phoenix Stadium in Glendale October 4, 2015.
Michael Chow/azcentral sports

Photos: Tyrann Mathieu

Arizona Cardinals Tyrann Mathieu (32) celebrates his 33-yard interception return against the San Francisco 49ers in the first half on Sep. 27, 2015 in Glendale, AZ.
Rob Schumacher/azcentral sports

Photos: Tyrann Mathieu

Arizona Cardinals free safety Tyrann Mathieu (32) celebrates his interception against the San Francisco 49ers in the 2nd quarter of their NFL game Sunday, Sept. 27, 2015 in Glendale, Ariz.
David Kadlubowski/azcentralsports

Photos: Tyrann Mathieu

LSU Tigers cornerback Tyrann Mathieu speaks during a press conference before the announcement of the 2011 Heisman Trophy winner at the Marriott Marquis in downtown New York City.
Jerry Lai-USA TODAY Sports

Photos: Tyrann Mathieu

Arizona Cardinals Tyrann Mathieu against the San Diego Chargers during preseason action at the University of Phoenix Stadium in Glendale, AZ., Saturday, August 22, 2015.
Rob Schumacher/azcentral sports

Photos: Tyrann Mathieu

Tyrann Mathieu, recovered from injuries that held him back last season, is optimistic about having a good year in 2015.
Tom Tingle/The Republic

Photos: Tyrann Mathieu

Photos: Tyrann Mathieu

LSU Tigers defensive back Tyrann Mathieu (7) reacts after a long punt return against the Georgia Bulldogs during the second half of the 2011 SEC championship game at the Georgia Dome in 2011.
Daniel Shirey-USA TODAY Sports

Photos: Tyrann Mathieu

LSU Tigers cornerback Tyrann Mathieu (7) talks during media day for the 2012 BCS National Championship game to be played on January 9, 2012 against the Alabama Crimson Tide at the Mercedes-Benz Superdome.
Derick E. Hingle-USA TODAY Sports

Photos: Tyrann Mathieu

Louisiana State Tigers defensive end Tyrann Mathieu runs with the ball after catching a pass during the NFL Combine at Lucas Oil Stadium in 2013.
Brian Spurlock-USA TODAY Sports

Arizona Cardinals free safety Tyrann Mathieu (32) removes his helmet during a break against the New York Giants during the second quarter at University of Phoenix Stadium in Glendale, Ariz. December 24, 2017.(Photo: Michael Chow/azcentral sports)

That’s a pleasant euphemism for a pay cut, which Mathieu declined to accept. Mathieu, now a free agent, likely won’t have trouble finding employment quickly.

Mathieu was due to have $18.75 million of his contract guaranteed if he was on the roster at 1 p.m. on Wednesday, the start of the 2018 NFL season.

By releasing Mathieu, the Cardinals free $4.8 million in cap space, but Mathieu will account for $9.3 million under the salary cap. The Cardinals decided to take the cap hit all in one year rather than designate Mathieu as a June 1 release. That would have spread the cost over two years, but Mathieu would have stayed on the books until June 1.

“I’ve never made a secret that Tyrann has always had a special place in my heart and always will,” Cardinals General Manager Steve Keim said in a release. “While we all understand this a part of the business, that certainly doesn’t make it any easier. We all wish Tyrann nothing but continued success in his career and beyond.”

Mathieu, a third-round pick in 2013, is among the more popular players in team history. The Cardinals took a risk by drafting him because Mathieu had been kicked off the team at LSU after testing positive several times for marijuana.

But Keim and former coach Bruce Arians believed in Mathieu, who changed his life and became a dynamic force on the field.

Via Twitter, Mathieu expressed appreciation for the Cardinals.

“I want to THANK the entire cardinals organization for everything they have done for me over the past 5years. Personally thanking Michael, Steve & B.A for believing in me. I will miss the fans and my teammates more than anything! My work in the Arizona community will continue!”

I want to THANK the entire cardinals organization for everything they have done for me over the past 5years. Personally thanking Michael, Steve & B.A for believing in me. I will miss the fans and my teammates more than anything! My work in the Arizona community will continue!

Remember in Hs and college watching Honey Badger highlights, Tremendous Respect for you, going to Miss sharing the field with you my guy, Welcomed me in with open arms, Giving me more knowledge than you will ever know, I’ll See you at the top! @Mathieu_Era

That deal paid Mathieu $21.25 million guaranteed but was designed to be evaluated in 2018. If Mathieu had returned to the way he played in 2015, the Cardinals likely would not have asked him to take a pay cut.

It’s unknown exactly what the Cardinals offered, but an NFL source said the team didn’t ask Mathieu for a drastic pay cut.

On Tuesday, the two sides were optimistic a deal could be reached, but that had disappeared by Wednesday morning.

Mathieu played in all 16 games last season for the first time in his career and showed improvement over the latter half of the year. He played more snaps in 2017 than any other NFL player.

During last season, Mathieu admitted he got off to a slow start and that his 2015 performance was both a blessing and a curse.

“Once you set a standard in this league, if you play under it, it’s not good enough,” Mathieu said in November. “Obviously, there was a three-,four-game stretch where I can look in the mirror and say, ‘What the hell was I doing?’"

Mathieu improved over the second half of the season, and the Cardinals envisioned a role for him under new coach Steve Wilks, albeit at a reduced salary.

Glad I got to play wit you my boy @Mathieu_Era I know you gone ball wherever you land‼️‼️